G Protein Coupled Receptor Kinase 7 (GRK7)

G protein-coupled receptor kinase 7 is a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinase family. It is specifically expressed in the retina and the encoded protein has been shown to phosphorylate cone opsins and initiate their deactivation.GRK7 encodes a deduced 553-amino acid protein with a calculated molecular mass of 62 kD. The protein contains a CaaX motif for isoprenylation and carboxymethylation of the C terminus, an autophosphorylation site at ser491, and a motif for geranylgeranylation. GRK7 shares 85% and 59% amino acid identity with the pig and medaka fish GRK7, respectively, and 47% identity with GRK1. Immunocytochemistry showed positive staining for GRK7 in the nuclear layers, the inner and outer plexiform layers, and the inner segment layer.